Pipe joints or couplings – Essential catch
Reexamination Certificate
2000-04-12
2001-03-27
Arola, Dave W. (Department: 3627)
Pipe joints or couplings
Essential catch
C285S317000, C285S323000, C285S328000
Reexamination Certificate
active
06206435
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a quick coupling device for coupling a tube to a rigid endpiece.
BACKGROUND OF THE INVENTION
To connect a tube to an installation or to connect two tubes to each other, it is known to use rigid endpieces of the spigot type having Christmas-tree shaped teeth, in which the rigid endpiece possesses a cylindrical tubular portion fitted on its outside surface with catching sharp edges that retain the tube and that seal the connection once the cylindrical portion has been forced into the tube. The main drawback of such a device lies in difficulties associated with assembly and disassembly. In order to guarantee good retention and good sealing, the teeth must be of sufficient height to bite properly into the inside surface of the tube, and as a result hand assembly becomes extremely difficult since it is necessary to develop large engagement forces, and disassembly becomes practically impossible because the teeth penetrate into the inside wall of the tube and their substantially radial surfaces oppose a force tending to pull them out.
In certain applications, it is nevertheless useful to be able periodically to make and break connections between a tube to a rigid endpiece easily and by hand. This can be made easy by significantly reducing the height of the teeth, however that is to the detriment of the quality of retention and of sealing achieved between the endpiece and the tube.
To remedy this drawback, is it known to band the tube, once installed on the endpiece, with at least one collar or ring that is placed on the outside of the tube and that is clamped thereon by appropriate means.
Such devices provide mechanical qualities that are satisfactory, however connection and disconnection operations require enough time to operate the clamping means. Further, when connection and disconnection are frequent, the indentations formed repetitively by the collar in the tube end up by damaging the outside surface thereof and can lead to a weakening in the retention provided by the banding collar on the tube.
Quick coupling devices are also known for coupling a tube to a rigid endpiece, which devices comprise a female part secured to the rigid endpiece and a male tubular part fitted to the end of the tube to be coupled. The female part has a stepped bore including a large diameter portion capable of receiving a shoulder of the male part beyond an axial latch. The male part generally has an elongate portion with a cylindrical outside surface fitted with retention projections (e.g., Christmas-tree shaped teeth) for providing non-dismountable connection between the tube and the male part.
With that kind of device, initial coupling takes place in two stages. The tube must first be fitted on the male part and this requires large engagement force since the clamping must be strong enough to ensure that the connection is leakproof. Thereafter, the male part must be inserted into the female part until the shoulder of the male part has gone past the axial latch of the female part, with the connection being sealed by means of O-rings disposed between the two parts. The tube is disconnected by acting on the axial latch so as to decouple the male part from the female part.
That kind of device thus makes it possible to perform frequent connections and disconnections without damaging the mechanical qualities of the coupling formed. However, the structure comprising two separate male and female parts is inconvenient in use and initial coupling requires special tooling and handling for the purpose of engaging the tube on the male part.
U.S. Pat. No. 5,314,216, issued to UMEZAWA for THIN RESIN TUBE CONNECTING COUPLING WITH FLANGE INSERT, discloses a coupling provided with a body having opposed front and rear ends. A large diameter chamber extends into the rear end and a communication hole extends into the front end. A small diameter chamber connects the communication hole and the large diameter chamber. A split annular grip with an inwardly directed annular pawl is disposed in the small diameter chamber and is dimensioned for surrounding the tube. All of the components inserted in the staged bore are extracted therefrom, with the tube. In other words, the banding ring is not extracted by itself, as it is in the present invention. The banding ring cannot move with respect to the latch, with or without a tube. In the present invention, however, the banding ring may or may not pass the latch, depending on the radial position thereof.
SUMMARY OF THE INVENTION
The present invention seeks to provide a quick coupling device of the above-specified type which is simple and compact in structure and which is extremely simple to implement, in particular on the occasion of initial coupling.
To achieve this end, the invention provides a quick coupling device for coupling a tube to a rigid endpiece including a female part secured to the rigid endpiece and in which a staged bore is provided that presents a section of large diameter beyond an axial latch that is movable between two positions, the device comprising a banding ring housed in removable manner in the large diameter section and fitted on its inside surface with at least one retaining projection forming axial connection means between the tube and the banding ring by biting into the outside surface of the tube, the axial latch in one of its two positions opposing axial displacement of the banding ring away from the rigid endpiece and, in its other position, releasing the banding ring.
Thus, the device is in the form of a part that is compact, the banding ring being integrated in the female part. On initial coupling, when the tube is inserted into the female part, the retaining projection of the banding ring fixes the ring permanently on the tube. This insertion can be performed by hand insofar as clamping of the banding ring on the tube does not serve to provide sealing, with sealing being provided directly between the female part and the tube. The axial latch prevents the tube from being disconnected by opposing axial displacement of the banding ring away from the rigid endpiece. To disconnect the tube fitted with its banding ring, it suffices to release the axial latch to allow the banding ring to pass and disconnect the tube which remains fitted with its banding ring. If it is desired to recouple the tube to the endpiece, it then suffices to slide the tube fitted with its ring inside the female part until the ring has gone past the axial latch. After the latch has been engaged, the tube is again prevented from moving axially inside the female part.
The banding ring may have a conical bore that converges towards the rigid endpiece and that has a small diameter that is smaller than the outside diameter of the tube, or it may have a cylindrical bore that is fitted with at least one retaining tooth.
In an advantageous embodiment, the banding ring comprises a split ring mounted in a cage which cooperates with the split ring via a conical contact surface that diverges towards the rigid endpiece.
It is then advantageous for the banding ring to include means for locking the split ring in at least one of the axial positions of said ring relative to the cage.
REFERENCES:
patent: 5314216 (1994-05-01), Umezawa
patent: 5711550 (1998-01-01), Brandt
patent: 9212228 (1992-11-01), None
patent: 4241817 (1994-06-01), None
patent: 2705430 (1994-11-01), None
patent: 8100747 (1981-03-01), None
Arola Dave W.
Legris S.A.
Salzman & Levy
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